Ernst Weber

Critical Conditions in Ferroresonance

THE APPLICATION of “ferroresonant” circuits to engineering problems has become increasingly important from both theoretical and practical considerations. While much progress has been made in the general study of ferroresonance, treatment is lacking in an accurate description of, perhaps, the most interesting part of the phenomena, namely, the so-called critical points at which the current suddenly changes in value. From a practical viewpoint, it is this characteristic property that makes ferroresonant circuits useful as sensitive elements in relay and control apparatus. Accordingly, there is a definite need for simple quantitative information that completely predetermines the behavior of the circuit under critical conditions and specifies the required circuit parameters in terms of known quantities.

The engineer and society

The engineering profession faces severe challenges in basic technological problems whose solution involves the behavioral and social sciences, and affects the very structure of society. As a consequence, the engineering profession must cast aside the last vestiges of its evolution from a craft and take on the full responsibilities of a learned profession

The Challenges in the Development of Graduate Programs

In order to protect the integrity of graduate degrees, the basic objectives of graduate study must be examined and interpreted in the widest sense, taking into consideration changing social conditions. This paper traces the development of graduate engineering education from World War I, with its original attachment to the established pattern of graduate study in university science departments. It considers the place of research in graduate study and the problems arising from the need for research sponsorship today. Also, attention is focused upon the classification problems arising from the large number of parttime graduate students enrolled in engineering schools today.

Traveling waves on transmission lines

THE USE of the Laplacian transformation in combination with tables of Fourier integrals reduces the solution of transmission-line problems to the same status as evaluating definite integrals by means of tables of integrals. Though this extension of operational methods is as yet unfamiliar to many, its great power, if once grasped, will rapidly increase its use.

Die magnetischen Felder in leerlaufenden Synchronmaschinen

ZusammenfassungEs wird für die Synchronmaschinen eine Normal-Leerlaufcharakteristik aufgestellt, welche einen sehr guten Mittelwert sowohl für Schenkelpol- als auch für Nutpolmaschinen darstellt und den Zusammenhang zwischen Ständerspannung und Erregerstrom typisiert. Der mathematische Ausdruck für die Leerlaufcharakteristik ist ein außerordentlich einfacher

“Knowledge is proud that he has learn'd so much: Wisdom is humble that he knows no more.”

\frac{E}{{En}} = 1,584\left( {1 - e^{ - \tfrac{i}{{i_n }}} } \right)

IEEE support of the UEC fund campaign

und dürfte sich für viele Probleme als sehr fruchtbar erweisen. Die gegebene Normal-Leerlaufcharakteristik wird zur Berechnung der mittleren Feldkurven der beiden Maschinenarten verwendet, welche Kurven ungenutete Eisenkörper für Ständer und Läufer voraussetzen. Bei der harmonischen Analyse zeigt sich die günstige Einwirkung des verlaufenden Luftspaltes bei den Schenkelpolmaschinen.Endlich wird auch der Einfluß der Läufernutung in Nutpolmaschinen und jener der Ständernuten in Schenkelpolmaschinen untersucht. Die allgemeine Feldkurve wird damit für Nutpolmaschinen durch die harmonischen Wellen der Ordnungen